OPTICAL FILM AND METHOD AND APPARATUS FOR PRODUCING THE SAME

摘要

Provided is a method for producing an optical film wherein unevenness in thickness and optical distortion are prevented sufficiently by a melt casting film deposition process. By the method, an optical film is produced by extruding a film composition material containing a molten thermoplastic resin from the lip of a casting die into a shape of a film, and then holding the melt between a pair of rotary rolls, thereby cooling and solidifying the melt. A shield plate is provided in the vicinity of the inlet of a nip in the pair of rotary rolls and in the vicinity of the surface of at least one of the pair of rotary rolls, and the shield plate is heated in order to heat an air flow produced through rotation of the rotary rolls.